1. Field of the Invention
The present invention relates to a semiconductor device having a mount board in which a module board provided with one or a plurality of electronic components is mounted on a socket and, more particularly, to a technique of cooling the module board mounted on the mount board.
2. Description of the Related Art
In electronic devices such as a personal computer or a server, a conventional memory device such as a DRAM (Dynamic Random Access Memory) device is directly mounted on a motherboard (mount board). However, in up-to-date memory devices, a memory module board on which one or a plurality of memory devices are mounted on a printed circuit board is prepared separately from a mount board, and is mounted on the mount board by a socket provided on the surface of the mount board.
In a memory module board, the amount of heat generated in the memory devices increases in accordance with the development of a higher density of memory devices mounted and increase in the read/write speed thereof.
The increase in the amount of heat generated in a memory device has involved an excessive temperature rise in the memory module board. This causes a problem of operation errors and system down in the electronic devices.
To prevent operation errors and system down in the electronic devices and to ensure excellent operation characteristics of the electronic devices, temperature of the memory module board has to be prevented from excessively rising by efficiently diffusing the heat generated in the memory module board, to thereby suppress occurring of a thermal runway. Patent Publications JP-A-2004-079940 (FIG. 2), JP-A-2003-017634 (FIG. 1), and JP-A-2001-118984 (FIG. 1) describe that various heat radiation members are provided on the side surfaces of a memory module board, on which memory devices are provided, to radiate heat from the side surfaces of the memory module board, thereby suppressing the temperature rise thereof.
In the memory module boards used in recent years, the higher density and higher processing speed of the memory devices have considerably increased the mount of heat generated therein. Therefore, it is difficult to sufficiently suppress the temperature rise of the memory module board simply by radiating the heat from the side surfaces of the memory module board, and to ensure superior operating characteristics of electronic devices.